3 8 9 5N78-7 SA CR-134950(NASA-C-13950) ENERGY CONSERVATION

ALTERNATIVES STUDY (ECAS): CONCEPTUAL -76.064-4 DESIGN AND IMPLEMENTATION ASSESSMENT OF A Unclas -- 4 UTILITY STEAM PLANT WITH CONVENTIONAL Unla 09159 FURNACE AND NET LIE STACK GAS SCRUBBERS

00044

ENERGY CONVERSION ALTERNATIVES STUDY (ECAS)

CONCEPTUAL DESIGN AND IMPLEMENTATION ASSESSMENT OF A UTILITY STEAM PLANT WITH CONVENTIONAL FURNACE

AND WET LIME STACK GAS SCRUBBERS

Dale H.Brown Corporate Research and Development

General Electric Company Schenectady, New York 12301

Contract NAS3-19406

Prepared for

ENVIRONMENTAL PROTECTION AGENCY TENNESSEE VALLEY AUTHORITY

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION ENERGY RESEARCH AND DEVELOPMENT ADMINISTRATION

NATIONAL SCIENCE FOUNDATION REPRODUCED BY

, NATIONAL TECHNICAL 1,INFORM4TION SERVICE,

.... SPRINGFIELD VAd22161tIlS. DEPARTMENT OFCOMMERGE '

https://ntrs.nasa.gov/search.jsp?R=19780073904 2020-04-08T20:43:13+00:00Z

This report was prepared with partial support

of the NSF Award AG 551 and ERDA IAA No. E (49

18)-1751; however, any opinions, findings, con

clusions, or recommendations expressed herein

are those of the authors and do not necessarily re

flect the view of NSF and ERDA.

NOTICE

THIS DOCUMENT HAS BEEN REPRODUCED

FROM THE BEST COPY FURNISHED US BY

THE SPONSORING AGENCY. ALTHOUGH IT

IS RECOGNIZED THAT CERTAIN PORTIONS

ARE ILLEGIBLE, IT IS BEING RELEASED

IN THE INTEREST OF MAKING AVAILABLE

AS MUCH INFORMATION AS POSSIBLE.

FOREWORD

The technical work described in this report is part of the EnergyConversion Alternatives Study (ECAS), a cooperative effort of the Energy Research and Development Administration, the National Sdience Foundation and the National Aeronautics and Space Administration. This,effort, performed under NASA Contract NAS3-19406, was sponsored by the Tennessee Valley Authority, under their activity TV-41967A and under Interagency Agreement EP-1-AG-D5-0721 with the Environmental Protection Agency.

The evaluation reported here in was undertaken on a basis consistent with Phase fl of the Energy Conversion Alternatives Study. However, the various aspects of this evaluation are completely and independently presented. The basis for this study is presented in an appendix.

In addition to the principal author listed, members of the technical staffs of the following organizations developed information for this study:

General Electric Company

Electric Utility Systems Engineering Department Corporate Research and Development Large Steam Turbine-Generator Department Technical Resources Planning, Turbine Operations Technical Resources Staff

Bechtel Corporation

Foster Wheeler Energy Corporation

A summary of ECAS reports is as follows:

Energy Conversion Alternatives Study (ECAS), General Electric Phase II Final Report, NASA CR-134949, Westinghouse Phase I Final Report (NASA CR-134942); Burns and Roe/United Technologies Phase II Final Report (NASA CR-134955); and NASA Report (NASA TM X-73515).

iii

SUMMARY

Conceptual Design and Implementation Assessment of a Utility Steam Plant with Conventional Furnace and Wet Lime Stack Gas Scrubbers

A conventional steam power plant with a radiant furnace and a wet lime stack gas scrubber system was evaluated to determine its potential use for baseload power generation. A conceptual design was established, including major components, plot plans, and power plant arrangement drawings. The wet lime scrubbing system was sized to remove 90 percent of the sulfur from the stack gas when coal having up to 4.5 percent sulfur was fired. The reheat of the scrubbed gas at 125 F was accomplished by adding steam-heated air; in a base case study, the stack gas is reheated to 250 F and in an alternate case the stack gas is reheated to 175 F.

The evaluations were made using the same groundrules and methodology as those followed for the Atmospheric Fluidized Bed (AFB) and the Pressurized Fluidized Bed (PFB) advanced steam power plants and other advanced energy conversion systems in Reference 1. A comparison of the results from this study and from Reference 1 for advanced steam power plants (all plants meet environmental emission targets) is presented in Table A.

Table A

SUMMARY OF PERFORMANCE AND COSTS FOR FOUR STEAM POWER PLANTS

Atmospheric Pressurized Conventional Conventional Fluidized Fluidized Furnace Furnace Bed Bed

Stack Temperature 250 F 175 F 250 F 300 F

Total Capital 835 771, 632 723 Cost,$/kWe

Cost of Electricity,* 39.8 37.0 31.7 34.1 mills/kWh

Overall Efficiency, % 31.8 33.8 35.8 39.2

*At an assumed capacity factor of 65%

All elements of the conventional plants are state-of-the-art, whereas the AFB and PFB plants incorporate major components that are not state-of-the-art. The use of steam to provide stack gas reheat for the conventional plants reduced the net plant electrical output and overall efficiency and increased plant cost per kilowatt of net output relative to conventional plants without scrubbers.

The total capital cost is based on estimated mid-1975 plant costs plus escalation and interest over a five and one-half year construction period beginning in 1975. The cost of electricity was based on coal at $1 per million Btu, an 18% per year fixed charge rate on capital costs, and included-estimates of operating and maintenance costs.

1. Corman, J. C., et al., Energy Conversion Alternatives Study (ECAS), General Electric Phase II Final Report, NASA CR-134949, 3 vols., NASA Lewis Research Center Contract NAS3-19406, GE Corporate Research and Development, Schenectady, N. Y., December 1976. PPrecTpeding pageln

A qualitative implementation assessment was made for the conventional steam power plants against a set of implementation factors for application in electric power generation. These factors were selected as representative of both the tangible and the intangible considerations that influence a power plant selection by an electric utility. The rating was performed by a panel of suppliers of equipment and services to the end user, the Nation's utilities, but not by utility representatives. No attempt was made to weight the factors nor to develop an index of their composite effect on the competitiveness of alternate energy conversion systems.

vi

TABLE OF CONTENTS

Section

1 INTRODUCTION . . .. ... .. ... .. 1

2 CYCLE DESCRIPTION ....................

5

Steam Turbine-Generator Cycle........... . 5 5 7 7 7 8

Conventional Steam Generator............ .Wet Gas Scrubbers. . ..............

Lime and Sludge Systems.... . . . . . . . .. Stack and Reheat System............

Overview ................. ........

3 MAJOR CYCLE COMPONENTS ....... ........... 9

Page

Conventional Furnace--Steam Generator ........... 9

Steam Turbine-Generator ......... .......... 9

Stack Gas Scrubber System ..... .......... ..... 13

Scrubber Costs ......... ........... ..... 18

4 PLANT ARRANGEMENT ...... ............. ..... 23

Plot Plan ......... .............. ...... 23

General Arrangement ...... ......... ...... 23 Electrical Schematic ...... ........... ..... 26

5 SYSTEM PERFORMANCE AND COST ........... .... 29

Performance Integration ..... .......... ...... 29

System Output ....... ............. ...... 30

Costs-General.......... . . . ...... 31

Major Component Characteristics. ... . . . . . ... 31

Major Component and Subsystem Capital Cost . 32

Balance of Plant Equipment List .... ..... .... 33

Balance of Plant Capital Costs ... ........ .... 33

Plant Cost Estimate ..... ........... ...... 44

6 NATURAL RESOURCES AND ENVIRONMENTAL INTRUSIONS. 47

Sensitivity to Emission Targets ..... ........ .... 48

7 SUMMARY OF PERFORMANCE AND COST ....... ..... 49

8 ALTERNATIVE PLANT CONSIDERATIONS .......... .... 51

Stack Gas Reheat to 175 F ...... .......... .. . 51

Performance and Cost-175 F Stack. ......... 53

No Scrubber, 250 F (394 K) Stack Alternative ... ...... 53

9 COMPARISON OF FUTURE ALTERNATIVES .......... ... 71

Overview .......... ............... .... 73

vil

TABLE OF CONTENTS (Cont'd)

Section Page

10 IMPLEMENTATION ASSESSMENT ..... ........... .... 75

Implementation Assessment Factors ........... .... 76

Appendix I-EVALUATION BASIS ....... .... ................. 85

Appendix 11-CRITERIA FOR IMPLEMENTATION ASSESSMENT FACTORS.. 89

LIST OF ILLUSTRATIONS

Figure Page

1 Conventional Steam Plant-with Wet Gas Scrubbing ........ 1

2 Conventional Steam Cycle with Wet Gas Scrubbers ... ..... 6

3 ECAS-il Conventional Boiler-Supercritical Once-Through Coal

Firing; 860 MWe ........ .............. .... 10

4 Conventional Steam Plant Flow-860 MWe ....... ...... 11

5 Conventional Furnace with Wet Scrubbers-250 F Stack . . 12

6 Steam Turbine-Generator, Preliminary Outline ...... ..... 14

7 Process Flow Diagram .... ............... ....... 15

8 Wet Gas Scrubber Arrangement-Conventional Steam Plant 19

9 Plot Plan for Conventional Steam Plant ......... ..... 24

10 Turbine and Boiler Buildings .... .......... ...... 25

11 Elevation View of General Arrangement ......... ...... 27

12 Major Electrical Equipment ..... ......... ....... 28

13 Conventional Steam Plant with Wet Gas Scrubber-175 F. . 54

14 Solids Requirement ...... ............. ....... 73

15 Water Requirement ..... ................ ...... 73

16 Gaseous Emission Characteristics (Lb/10 6Btu Input) . . .... 74

LIST OF TABLES

Table Page

1 System Parameters ............ .............. 2

2 Limestone/Lime System Parameters .... .......... .... 16

viii

5

10

15

20

25

30

LIST OF TABLES (Cont'd)

Table Page

3 Wet Lime Absorber System Parameters .... ........ .... 17

4 Flue Gas Heaters for Wet Scrubber Systems ... ...... ... 18

Scrubber Equipment Direct Field Costs (250 Stack Temperature). 20

6 Scrubber Equipment Direct Field Costs (175 Stack Temperature). 20

7 Wet Lime Scrubber Capital Cost Breakdown

(250 F Stack Temperature) ....... ............

9 Energy Balance---100 Percent Rating, 59 F Day ..... ..... 29

.... 21

System Output ......... ............... .... 30

11 Auxiliary Loss Breakdown ...... ............ ..... 30

12 Heat Exchanger Characteristics ..... ........... ..... 31

8 Wet Lime Scrubber Capital Cost Breakdown

(175 F Stack Temperature) ...... ............. .... 21

13 Major Component and Subsystem Weights and Costs Summary. 32

14 Major Component and Subsystem Capital Cost Summary . . . 32

Balance-of-Plant Equipment List .......... ......... 34

16 Balance of Plant Estimate Detail for Conventional Steam Cycle-

Wet Gas Scrubber-250 F Stack .......... ........ 37

17 Plant Capital Cost Breakdown . ..... ......... 44

18 Plant Capital Cost Estimate Summary .......... .. 45

19 Natural Resource Requirements... ...... ....... 47

Environmental Intrusion ............... ..... 48

21 Summary Performance and Cost .......... .... 49

22 Cost of Electricity (COE) Sensitivity .......... .. 50

23 Conventional Steam Plant Wet Gas Scrubbers-175 F Stack. . 51

24 Steam Turbine Cycle Changes .... ........ ...... 52

Auxiliary Loss Breakdown ..... ........ ....... 52

26 System Output ....... .............. ...... 53

27 Equipment List for Conventional Steam Cycle-Wet Scrubbers,

175 F Stack ......... ................. ...... 55

28 Balance of Plant Estimate Detail Conventional Steam Cycle-Wet

Lime Stack Gas Scrubber, 175 F Stack Gas ....... ...... 59

29 Balance of Plant Capital Cost Breakdown ........ ...... 65

Plant Capital Cost Estimate Summary ........... ...... 66

31 Summary Performance and Cost .. ............. .66

ix

LIST OF TABLES (Cont'd)

Table Page

32 Influence of Stack Reheat Temperature ........... 67

33 Cost of Electricity (COE) Sensitivity ............ 67

34 Auxiliary Loss Breakdown ................ .... 68

35 System Output ........... ............... 69

36 Capital Cost Distributions as $/kW ............. 71

37 Efficiency Order of Steam Plants . . ............ 72

38 Cost Distribution-Steam Power Plant. ........... 76

39 Summary of Operational Flue Gas Desulfurization Systems . . 77

40 Fuel Characteristics .............. ............ 85

41 Emission Standards ....... ........... ....... 86

42 Operating and Maintenance Costs Per Year ..... ....... 87

43 Implementation Assessment Panel ................. 90

x

Section 1

INTRODUCTION

A steam power plant with wet gas scrubber to reduce stack gas emissions has

characteristics distinctly different from the numerous conventional coal-burning steam

power plants that cannot meet today's emission standards except by burning low-sulfur

coal or converting to oil firing. There will be a direct competition between plants with

conventional furnaces with stack gas cleanup, and alternatives such as fluidized bed

furnaces that capture sulfur products during the corfibustion process. In this study a wet

lime scrubber was specified for use in the study of a conventional steam plant with stack

gas scrubber.

A simplified cycle schematic presented as Figure I shows the major pieces of equipment. The coal and air are fired with staged combustion of the pulverized coal to

limit generation of thermal NO x products. The boiler, steam turbine, condenser, and

cooling towers are all proven conventional elements. Gas leaves the unit at 300 F (422 K)

after passing through electrostatic precipitators that reduce the burden of fly ash in the

flue gas. The gas enters the scrubber and is quenched to 125 F (325 K) with lime slurry

sprays. Sulfur is removed as calcium sulfite and calcium sulfate, which precipitates out in

the sludge pond. Lime is continually replenished, using an on-site calciner for limestone.

Air LP

SteSteamA tu~

Re heatersStaCodne Stack

Gas tFeedwaterScrubbers FFeed Heaters

~Colciner

Sludge Pond Limestone

Figure 1. Conventional Steam Plant-with Wet Gas Scrubbing

I

The water-vapor-saturated flue gas at 125 F (325 K) is next reheated to the final

stack temperature. In this investigation two stack temperatures were studied: 250 F (394

K) and 175 F (353 K). The means of raising the temperature is a blending of the flue gas

with a large quantity of air that has been preheated above that temperature by steam

extracted from the steam turbine cycle.

The system parameters-are presented in Table 1. The Illinois No. 6 coal contains

3.9 percent sulfur. Eighty-three percent of the sulfur must be captured to meet the

environmental emission limit of 1.2 pounds of sulfur dioxide per million Btu of fuel heat

release (0.52 kg/GJ.) However, the wet scrubbers were specified to capture 90 percent of

the flue gas sulfur burden when 4.5 percent sulfur was present in the coal, to provide

margin in the design to enable burning of coals with sulfur content higher than 3.9

percent. With the specified margin of performance capability, the plant operation is

assured of meeting current standards for flue gas emissions. The consumption of lime is

minimized by the intimate mixing in the wet scrubbers. In addition the recirculating

system provides for reuse of lime in solution in the clarified water recirculated from the

sludge pond.

Table I

SYSTEM PARAMETERS CONVENTIONAL STEAM-WET GAS SCRUBBERS

PARAMETER VALUE OR DESCRIPTIONC FUEL

ILLINOIS NO. 6 10788 Btu/LB HIGHER HEATING VALUE I $/MBtu

LIMESTONE FOR SULFUR CAPTURE 0 16 LB/LB COAL

FURNACE

RADIANT SECTION PULVERIZED COAL FIRED CONVECTION SECTION SUPERHEAT AND REHEAT

PRIME CYCLE - STEAM PLANT WORKING FLUID STEAM TURBINE INLET 3500 PSI, 1000 F

REHEAT 659 PSI, 1000 F CONDENSER 2 3"Hga, 106 F FINAL FEEDWATER 4378 PSI 505 F

HEAT REJECTION WET MECHANICAL 20 CELLS DRAFT COOLING TOWERS STACK GAS TEMPERATURE 250 F

2

The steam cycle uses conventional conditions for a supereritical reheat unit with

seven feedwater heaters. The large extraction of steam at the turbine crossover pressure

for stack gas reheat approaches the limit set for conventional practice. The condenser

back pressure was chosen to optimize the total cost of electricity with respect to turbine

output and cost, heat rejection system cost, and auxiliary power consumption.

The stack gas temperature was set at 250 F (394 K) in conformance with

conventional steam power plant practice. The influence of stack gas temperature,

however, is far greater than normal for this steam plant configuration. Because corrosive

component dew points in the flue gas are at or below 125 F (325 K) as a ,esult of the

scrubbing process, a lower stack temperature was deemed to be of interest. A subsequent

evaluation was therefore made for 175 F (353 K) stack temperature in addition to 250 F

(394 K). Details of this case will be presented after a complete appraisal of the 250 F

(394 K) stack base case.

3

Section 2

CYCLE DESCRIPTION

A more detailed plant schematic for the 250 F (394 K) stack temperature case is

presented in Figure 2. State points and stream flows are shown wherein the enthalpy

values are referenced to 32 F (273 K) water for steam and water and to an 80 F (300 K)

zero reference for air, combustion gases, and solids. The advanced feature of this power

system is the use of wet flue gas scrubbers with a conventional boiler to generate steam

from high-sulfur coal for a conventional steam turbine cycle with a single reheat of the

steam.

STEAM TURBINE-GENERATOR CYCLE

The steam turbine is contained in four shells connected in tandem with a single 820

MW generator. The low pressure stages have four parallel flows exhausting downward into

a common condenser. The condenser coolant is water recirculated in a closed circuit to

evaporative cooling towers. The regenerative feedwater heating cycle has four low

pressure feedwater heaters, a deaerating feedwater heater, and two high-pressure

feedwater heaters. Part of the steam exhausted from the high-pressure turbine is used in

feedwater heating, while the rest is returned to the boiler to be reheated to 1000 F (811 K).

Part of the steam from the reheat turbine exhaust is used for driving the boiler feedpump.

The exhausts from the three drive turbines are routed to the main condenser. All other

pump drives are electric motor driven and appear in the detailed account of auxiliary

losses. The boiler feedpump and its drive are an integral part of the steam cycle and are

fully accounted for in the heat balance for the steam turbine-generator.

The final feedwater would be 505 F (536 K) for the 100 percent operation. All

major components were specified for continuous performance capability at a flow margin

of 5 percent above the intended plant operating flow. The steam cycle at the valves wide

open (VWO) point would pass the intended flow with margin, and the designated 510 F (539

K) feed temperature would then exist. It is important in conventional steam systems that

the operations be evaluated at the 100 percent operating point where performance is

guaranteed, and not at the specification condition for design with margin.

CONVENTIONAL STEAM GENERATOR

The coal to be fired is dried by the primary air-flow at the eight ball mill

pulverizers. Between 15 and 20 percent of the total air is heated to 633 F in the hiottest

5

Generated 8199MW CovninlSteam Trbine Generator (1) Auxiliaries 727MW

Stck (I ) Steam Generator 3515/1000/6.0/l421 e7 55/1335 Net Output 747 2 M W SI~ck I) (I)154/620/3

/ 147/250/22 39/334114 1516 jjStackAir J 134/620/09a/-Hig

139/125/80 13/35 Pressure Reheat Generato AFan (5)Fi 0.221

,(Makeup 0 6MWWater Air 59O rLime " SYSTEM Air Preheater CnnsrI (7U.l ICUBE _I To Sack

Stoe Calolnator L0MW S 4393/505/-L Air

012#66 ''Y FMWElectrostatic Pulverizers 0H

Cool/ /r |Precipitators T e High PSI @ @)eoerotlng

0 014v ' 10DFa ns Boler e d t p(o Fe e d He ate r- 3! 0

Fly Ash Prssr FeederHeaer MoeE M) Towers// //Scrubbers I6S Fy s AIR

Fly Ash20 Cells 0 0,58# 147/59/6427

@ Lw Pressure Feed Heaters MakeupWater

Sludge Pond(6) Boiler Feed Pump () [(T--TO3600' X 3600' X 22'

LEGEND' Pressure/ Temperoture/ Flow Rote/ EntholpyPSIA/F/Mihlion Pounds Per Hour/BTU Per Pound *MIIIIon Pounds Per Hour

Figure 2. Conventional Steam Cycle with Wet Gas Scrubbers

sector of the air preheater as primary air. This air serves to dry the coal, to convey the

pulverized coal to the burners, and to consummate the initial combustion process. The

remainder of the air is preheated to 585 F (580 K) and delivered to the burners as

secondary air.

The water circuitry in the steam generator provides water walls, radiant energy

absorption surfaces, convection and radiant surfaces for superheating and reheating of steam, and an econimizer to bring the flue gas to 740 F (666 K) as it leaves the boiler and

enters the air preheater. Slag is removed from the boiler furnace beneath the firing zone,

fly ash from a hopper just before the air preheater. These solids, representing 15 and 10 percent of the total ash, respectively, are sluiced to the sludge pond. The electrostatic

precipitators, with an efficiency of 98.6 percent, collect another 75 percent of the total

ash, leaving only 0.75 percent in the gas flow to the wet scrubbers. The collected fly ash

is stored in dry silos for shipment off-site. Induced draft fans follow the electrostatic

precipitators.

WET GAS SCRUBBERS

The wet gas scrubbers apply a spray of recirculated hot water that is rich in lime in

order to capture sulfur compounds. The remaining fly ash will be washed out of the flue

gas also. Following the main reactive spray there is a demisting spray that recirculates a

makeup water and captured drift mixture. Carry over of the slurry and lime are avoided

by this means.

LIME AND SLUDGE SYSTEMS

A continual removal of sludge and a continual replenishment of lime and water is required. The sludge is flushed to the sludge settling ponds in a stream comprising 10

percent undissolved solids. The return water from the pond is enriched with lime produced

in the coal-fired calcinator from limestone feedstock.

The makeup water moves in a counterflow mode. It is first used in the mist

eliminator recycle wash; the bleedoff replenishes the SO 2 absorber recycle liquids;

ultimately the makeup water becomes part of the sludge and water mixture that

accumulates in the settled portion of the sludge pond.

STACK AND REHEAT SYSTEM

The flue gas at 125 F (325 K) leaves the wet scrubber saturated with water vapor

and with many constituents at or near their dew point temperatures. It has been

7

determined that normal gas heaters cannot have suitable service lives when heating such a

corrosive gas mixture. The alternative to direct heating is to blend into the flue gas a large flow of air that has been separately heated. Figure 2 shows that 14 Mlb/h (1764 kg/s) of air heated to 334 F (441 K) blend with 8 Mlb/h (1008 kg/s) of flue gas to produce a 250 F

(394 K) stack temperature. The stack air heaters use steam withdrawn from the steam

cycle as their heating medium. The stack and flues are lined to withstand attack from the flue gases.

OVERVIEW

The major components of this system are conventional and of proven reliability in utility service. The wet scrubber system introduces added equipment requiring

maintenance, and also the need to avoid the corrosive effects of lime and of cool flue gas.

The subdivision of scrubber duty into six parallel scrubbers and the subdivision of critical

pumping functions in the scrubber system should assure that at most one-sixth of the

capacity would be down at any time.

8

Section 3

MAJOR CYCLE COMPONENTS

Components for conventional steam plants are specified for continuous operation

with flows 5 percent greater than required for normal operation. insofar as Figure 2

depicts 100 percent plant operation on a 59 F (288 K) day, the individual specifications for

the boiler, turbine, and scrubber will require greater capacities at their design points. The

exact matching has been accomplished on the basis of an exact steam-turbine heat

balance, which dictates the heat to steam for the boiler, and the boiler efficiency, which

in turn dictates the fuel requirement.

This section will consider the specified performance for the steam turbine

generator, the boiler, the scrubber system, and the heat rejection system. The latter two

are furnished as balance of plant equipment. All other balance of plant itdmg will be

specified in a subsequent section.

CONVENTIONAL FURNACE-STEAM GENERATOR

The general layout of the conventional supereritical once-through steam generator

is shown in Figure 3. Eight ball mill coal pulverizers are located at the base elevation.

The burners are arrayed about the radiant furnace section. The combustion gas flows

upward over superheater sections, then downward in parallel paths through the reheater

and the primary superheater, and finally emerges from the economizer. Figure 4 presents

a preliminary heat-and-mass balance at the specified design flows. The final

configuration differed from that shown in that the induced draft fans (IDF) were located

after the electrostatic precipitators instead of ahead of these units. All other features

were the same and the flows, temperatures, and pressures are correct as shown. The heat

to steam for this boiler was 87.1346 percent of the fuel higher heating value.

STEAM TURBINE-GENERATOR

The heat balance for the steam cycle is presented in Figure 5 for operdtion at the

100 percent rated power condition of 820 MW. The rating at the valves wide open (VWO)

point would be 860 MW. The seven feedwater heaters and the throttle and reheat

conditions are typical for supercritical reheat units today. The unusual feature is the

extraction of 926,000 lb/h (117 kg/s) of steam for stack gas heating service. The-effedt on

the steam turbine cycle is as if a separate condenser were located at the 134 psi level.

9

SUPERHEATER UTLET

- - 4I

PLT P RI[TARY SUPERHEATER

20 H DEiPTHl PLATEN$ERI

',lE r ONO IZER

INLET

_, " IAC E WIDTH'" "1410"?,

0 QRN. !s I r i:?Pri46] E DEPTH INLE .OPUEL 3& r'n

85'10 4-'IZ

"~~

Figure 3. ECAS-II Conventional Boiler-Superertical Once-Through

Coal Firing; 860 MWe

10

FSH~6 2850M - 36000/1005°0

S S FWEC-0-59-6023S869 Stean Pl ntS/ 86 MOil

.7575 m Sil 00 6.2850;,azI 4350#80- Pump PA 510Furnace °

99 15570.COAL

MO. 90 m WY--4o022ater

II40°/-2 290° Chemca

V 1Ps126 2506 m us59o~Ilos _6 - 8 822 m gas 86N 010 Ti 000566m dust

8 Lls-. - 61 1 Slurry

l596F33i 4 nSP 41L 5L54"FUE D 0190m,3778 m 6,6882M * 07183m Dus _

Illinois #6 Slag 007272m dus-PF F£

HHV - 10788 Btu/# Ash Disposal

C .5960 *BY GEC/BECHTSL

H 0590 °- Temp (*F)

S .0390 - Press.(psia)

0 .2000 "- Press (In1120)

N 0100 - Flo. (M?//Ir

ASH .0960

na = .871346

Figure 4. Conventional Steam Plant Flow-860 MWe

I,1 Cr liD GaIruI tionn based on

L.--2- - "-: ' --5

" q -"'

14.P13 30 "( v-" 1515 610 '1421 7041 I0OO

7H0300's 134162013, 549,423

Q EfTRAfIION

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TO *HTR -

T 3359.44

5320 700 9240 3E0015-, 0335 OH 1272 OH 03 I'FF 13

STACK 26 60r

GAS KIN 4HEATIN

A101

.5.7

40t

50 Ft N48 7/"T 47 176 0'P'I0 347N 4F L L - 27I00, o0--h

193 Zh1 h 8 Z61 Oh 195 71 D19 4o 9 I32

645,730 9 Z50,S8ZU

A7O7:' T PUMP

35 r 38 SF 600330 9h 3z 9h Ah : I 89 ZOR91

6 8674E9 Btts/h AssLnsms 90% CUiclency 0VALVE DEs POIra sOQ,313( L_ 43 Z) 5 3 7j7fl 5_6 m IZ7L1 -08414 I/11.11\ .0I1

N0 HEAr RATL 1 819,938 - 3697

GROSS NEAT RATE * 8375 54

1967 ASMr Steam 1 Ibes 11. h - 0Zntha00, pI0/Lb p - r , . Lb/FrP - 'Pro,-.ure, Psja

0- lemperature. F degre.

(LN ERATrOR OUTPUJT,

ARRANGE

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0 0, P 7 .01

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The reduction of steam flow to the low pressure stages reduces generator output and also

the condenser and cooling-tower heat rejection load.

The steam turbine comprises four shells. The high-pressure turbine, the reheat

turbine, and two double-flow low-pressure condensing turbines are arranged in tandem

with the single generator.

The foundation and arrangement drawing of Figure 6 gives the overall dimensions

of the unit. The last-stage turbine buckets are 33.5 inches (851 mm) long. These are the

largest buckets applied to 3600 rpm turbines for fossil-fired service. The unit is

characterized as "TC4F33.5," indicating tandem compound, four Cxhaust flows, with 33.5

inch (851 mm) last-stage buckets.

The heat to the steam cycle at-100 percent operating conditions would be 686.7.4

MBtu/hr (2.01 GJ/s). The heat input would be 8375.54 Btu/kWh (8.84 kJ/kWh), for

generator output.

STACK GAS SCRUBBER SYSTEM

Although all elements of the wet gas scrubber system would befurnished as balance

of plant equipment, the unique aspects of this system suggest that it be discussed as a

major cycle component.

The entire scrubber system is illustrated in Figure 7 along with process flow charts

appropriate for operation at the specified 5 percent flow margin, using 4.5 percent sulfur

coal. The sulfur capture would be 90 percent. The two process flow charts do not differ

in respect to the sulfur capture system; only the reheating of stack gas to 250 F (394 K) in

the upper chart and to 175 F (353 K) in the lower chart ar different. -

The lime requirement is met by calcining limestone in a rotary kilm fired with coal.

There is on-site a 60 day supply of limestone. The coal is stacked in a four day storage bin

by front-end loaders. The emission requirements for the calciner are met by the use of a

baghouse dust collector anda separate stack. No reduction in sulfur gases is expected for

the coal fired in the calciner.

The lime product is expected to be in excess of 95 percent available lime. It is

stored in silos with a capacity sufficient for five days' operation. With the 1500 tons per

day (378 kg/s) of limestone calcining capacity, this part of the plant need not operate

continuously to support plant operations. There should be sufficient time to accomplish

13

-6FT6 T[TFT4 GFTr IF 0 7 FTT 4oFT" 19 F 4 6o1 - 24FY05

II k T I

CONTROLVALR 9 O GE

MAY BE WLTED ON 54 oo I FWJTIR 4000 4 afs BAS I0

IN FRONTOIp I-000P-V0 T,

BASAE 9 A T U cI 24OANhI4'

35.I LEAISTSTGE UCKG RESI ADDTINALLOD ONTIBTE STCOETSETNT ICLDE2.6HEVIES PICUIN RCIN EEATRSAO 7 DISTANCE REOUIRIEO TO REMOVE MAJOR PARTS -N0T INCLUDINGHEAVIESTPIECE AFTER ERECTIO.(GENEATOR FITsRE SLINGSIRO'OR W9LiCO0 LW3 ICO0 S 2W0C00 LB LOADINGS DOHOTOCCUR SIMULTANFOUSLy A GENERATOR.TATVE- 14 FTI EXHAUST0t BASE _N4 BUO ARE SUPERIUPOSE ON 40000A 16000T LOAB SPB OAD WIlOVOLVItIVMINALS0l ATTACHE

IS ZERO NORMALOPERATION FO FULL VALUE N OF -6MOR ELB WAD OO0 LB LOAD IS ZERO Q

4 TH f;M ',tLVIND RHEA $THIS OUTLINE SHALL HOT BE USEO FC* EONSTRUCTIDI IJRPQSESARRAG[MNT NCLUES4 THVAVECOBINDE ARANEMETRHEA ICLUES aETHE GENERAt =ECUIPMENT ARRANGEMENT PIE NBIONS ANDREHEAr STOP AND INTE'RCEpT VALVES LOADINGS ARC TO SC COSOE$DRE.OpRELIMI1NARY AND SUBJECTr

5 C-OCXISESH~t OTATONHENVIEWD FOM CLL TO LATER MODIFICATIONS O

SNSHAF GROTTO SCOXIEWHNVEE RMCLTOR 9 RECONIMflN;tO MINIMuM CRANE 140OK HE:IGHTABOVE TB, CGlNE EBASE LINE- FT7 IH

ID RECONMEN10 MIUIMUMFUNDA7TICHEIT- 40 Ft 15 ItHE HORIZONTAL ATT1 60M0C00TORNRCIS ACTING ETS ICLUDEAS FOI50

Figure 6. Steam Turbine-Generator, Preliminary Outline

En EAI4G AIR

6---I~~~ -- -----

KtSO, 1 .1 Us "s

CACWR E)IR IM.nINST.S~ St ARA 1oI0 VAJSKILIMETOIZ GATErI~,4ILH VSTO,AWLOG

ST..~f BAOOIOUSE, IC8FA oAY C L Y.. A.-. . E5F

tOL

~Al SCT0 ? OS3 I 0 03 0 01100M ? 00.0___ 343 '0 030414

IN(1 831S13-8 0)0

O W .. I3 .. I3 ..0000A0383~~~17 1 0 Il

. I I I 7011 235 11I50f" 3 80

RA UEF303 E ET 0 Il

I~igr I 7. Proes Flow DiagramAM

all usual maintenance and refurbishment on a scheduled basis. The entire left half of

Figure 7 represents on-site capital investment and operations that would be eliminated if

lime rather than limestone were available for purchase in suitable quantities at a suitable

price.

The right half of Figure 7 is the scrubbing system that causes lime to react with

sulfur in the flue gas to form solids that accumulate in the sludge ponds. The lime

replenishment is slacked with pond recycle water to a 16 hour storage tank. The slacked

lime and remaining pond recycle water are discharged to the So 2 absorber effluent holding tanks. Table 2 presents the major parameters of the limestone/lime system considered to this point.

Table 2

LIMESTONE/LIME SYSTEM PARAMETERS

CONVENTIONAL FURNACE--STEAM CYCLE

Parameter Value or Description

Lime Product Quaiity 95% available CaO

Limestone/Lame Product 2 tons/ton

Limestone Storage 60-day supply

90,000 tons

Limestone Calcner (Traveling

Grate Kiln)

Nominal Production 650 tons/day

Capacity 880 tons/day

Fuel Requirements (Ill. No. 6) 5 MBtu/ton lime

Lime Storage Capacity 5-day supply

Lime Slaker Capacity 800 tons/day

Slaking Temperature -190 F

Slaked Lime Slurry Solids (After 20% weight

Dalution)

Lime Slurry Surge Capacity 16 hours

The three-stage SO2 absorbers operate on flue gas that has been quenched from 300 F (422 K) and saturated with water vapor at 125 F (325 K) by the presaturation sprays at

each absorber gas inlet. The flue gas then flows upward through the three absorber

stages, each of which comprises a 6 inch (152 mm) bed of spheres. The liquid-to-gas ratio

maintains 110 percent of lime-to-sulfur stoichiometric ratio. The effluent wet gas is further washed in the mist eliminator sprays. These sprays receive all of the fresh

makeup water intended for all replenishment of the scrubber system. This final wash

captures carry over or large droplets of drift of recycle wash liquids. Table 3 identifies the parameters of the wet absorber system and keys the stream functions to Figure 7.

16

Table 3

WET LIME ABSORBER SYSTEM PARAMETERS CONVENTIONAL FURNACE--STEAM CYCLE

(Basis: 90% SOx Removal for 4.5% Sulfur Coal)

Parameter Value or Description

SO2 Absorbers (6) TCA type

Number of Stages 3 (6" of spheres/stage)

Superficial Gas Velocity 8 ft/s

Total Pressure Drop 9 in. H20

Liquid/Gas Ratio< 72 gal/mscf

Presaturation Sprays 7Q> 2.5 gal/mscf

gpm/ft 2

Mist Eliminator Wash Sprays

Table 4

FLUE GAS HEATERS

FOR WET SCRUBBER SYSTEMS

STACK GAS REHEAT TEMPERATURE PARAMETER 250 F 175 F

HEAT DUTY,'MBtu/HR 971 217

STEAM 620 -356 F 620 -356 F

AIR 333 459 F 333 459 F

AIR VELOCITY, FT/MIN 900 900

AIR RATE, MLB/HR 14.586 3.267

PRESSURE DROP, IN H20 1.5 1.0

HEAT TRANSFER RATE, Btu/(HR SQ FT OF) 5 5 10.4

FINNED SURFACE, SQ FT 645,000 86,500

The sludge ponds are the remaining element of the wet scrubber system. Each pond

would measure 3600 feet (1097 m) by 3600 feet (1097 m) by 22 feet (6.7 m) deep. Six ponds

would accommodate 30 years of plant operations. The accumulation rate of solids would

equal the solids delivery rate of 150,000 lb/h (18.9 kg/s) of calcium sulfite and excess

unreacted lime. Because water would accumulate at a rate 50 percent greater, in situ

solids concentration would be 40 percent. It is important to recognize these two

accumulations, because the tables on Figure 7 represent steady-state balances for the

absorbers but nonsteady states for lime, makeup water, and sludge accumulation.

SCRUBBER COSTS

The direct costs for the scrubber system comprise material costs and direct field

labor costs as detailed in Table 5 for a 250 F (394 K) stack and in Table 6 for a 175 F (353 K) stack. These costs are not complete insofar as balance-of plant construction must bear

a prorated share of the indirect field expenses and additional electrical, civil, process, ard yardwork must be done. Tables 7 and 8 present the complete costs, with the first two

items on line 1.0 carried over from Tables 5 and 6. The allocations for indirect labor, fees,

contingency, and escalation will be discussed in the subsection concerned with balance of

plant in Section 5, "System Performance and Cost." All of these items of expense will

also be included in the comprehensive list of balance of plant accounts. Presentation here

with all elements of costing is done to facilitate identification of the incremental cost due

18

- -

I

~~0 o __

SOIL __.

-- - t----':; : -- - I I, .I,- " I

\ I Qo I- -.-' ESP 2i 2

: WI --- P

____-_-.-2'?'_ I_'F

GROUND FLOOR PLAN EL 0O

-- - - D W EI--

,oI-' 1 .A,' ES IESP

I-c-iv ,r,- .2-' I = & O , 2i0

0

SECTION A-A & TYPICA-)

Figure 8. Wet Gas Scrubber Arrangement-Conventional Steam Plant

19

to the Wet sdrubber system. For the 250 F (394 K)stack case, a total of $51.9 million for

this major syst6m is cofnparable to ,a steam turbine-generator cost of $26 million, and a

,boiler componernieost of $39.7 million. The Wet scrubber is a major addition.

Table 5

SCRUBBER EQUIPMENT DIRECT FIELD COSTS f(25O'STACK TEMPERATURE)

MAJOR MECHANICAL MATERIALS DIRECT LABOR TOTAL

,EQUIPMENT . MS MS MS

LIMESTONE HANDLING 1.25 0.25 1:50

LIMESTONEILIME SYSTEM 3.66 0.78 4.44

502 SCRUBBER VESSELS 6.93 1.01 7;94 SCRUBBERSYSTEM PUMPS 1.08 0.12 1.2d

SCRUBBER SYSTEM TANKS 2.18 0.05 2.23

SCRUBBER DUcTWORk 3.27 2.43 5.7G

SCRUBBER FLUE GAS EQUIPMENT 3.09 0.32 3.41

TOTAL 21.46 4.d6 26.42

Table 6

'SCRUBBER ',EQUIPMENTiDIRECT 'FIELD COSTS '(175STACK 'TEMPEATURE)

MAJOR MECHANICAL MATERIALS DIRECT LABOR TOTAL. EQUIPMENT M$ M$ Ms

LIMESTONE HANDLING 1.2 0:25 1:50

,LI MESTONEILIME ,SYSTEM 3.66 0.78 4.44

SO2 SCRUBBER VESSELS 6.93 1.01 7.,94

SCRUBBER SYSTEM PwMS 1.08 0.12 1.26

SORUBBER SYSTEM TANKS 2.18 L0.05 '2.23.

SCRUBBER DUCTWORK 4 1.95 1.41 3.36

SCRUBBER FLUE GAS EQUIPMENT * 0.90 0:08.96

TOTAL * 17.95 3.70 21.65

*CHANGED FROM 250 'STACK CASE

L20

Table 7

WET LIMESCRUBBER CAPITAL COST BREAKDOW;N

CONVENTIONAL FURNACE--STEAM 'CYCLE

,(250 F STACK TEMPERATURE)

DIRECT INDIRECT'MATERIALS ,LABOR FIL -TOTAL

CATEGORIES MS M$ Mt MS

1 0 PROCESS MECHANICAL EQUIPMENT 21 5 '50 4:5 31.0 (LIMESTONE HANDLING, LIME SYSTEM, ABSORBERS, TANKS, PUMPS, AIR HEATERS, F.D. FANS, DUCTWORK)

20 ELECTRICAL 0.7 09 0.8 24

3 0 CIVIL AND STRUCTURAL 3.7 21 1.81 7.6

4 0 PROCESS PIPING AND INSTRUMENTATION 4.3 2 6 2.3 9.2

5.0 YARDWORK AND MISCELLANEOUS - 9 0.8 1:7 '51 9

AlE ENGINEERING,,HOMEOFFICE & FEE @15% 78

TOTAL PLANT COST 59.7

CONTINGENCY @ 20% 11 q

TOTALOCAPITAL COST 71 :8

ESCALATION & INTEREST DURING CONSTRUCTION 392

TOTAL PLANT INVESTMENT 1108

Table 8

WET LIME SCRUBBER CAPITAL COST BREAKDOWN

CONVENTIONAL FURNACE-STEAM -CYCLE

(175 F'STACK TEMPERATURE)

DIRECT INDIRECT

MATERIALS LABOR FIELD TOTAL

CATEGORIES MS MS MS MS

1 0 PROCESS MECHANICAL EQUIPMENT 17 95 3 7 '3.3 25.0 (LIMESTONE HANDLING, LIME

SYSTEM, ABSORBERS,

TANKS, PUMPS, AIRHEATERS,

F D. FANS, DUCTWORK)

20 ELECTRICAL 0.7 0.9 '0.8 24

30 CIVIL AND STRUCTURAL 37 21 1 8 76

40 PROCESS PIPING AND

38 25 22 85INSTRUMENTATION

5 0 YARDWORK AND MISCELLANEOUS - 09 08 117

45.2

68A/ErENGINEERING, HOME-OFFICE & FEE@15%

52 0TOTAL PLANT COST 104CONTINGENCY @ 20%

62 4TOTAL CAPITAL COST

ESCALATION &INTEREST DURING CONSTRUCTION 34 2

TOTAL PLANT INVESTMENT 966

,21

Section 4

PLANT ARRANGEMENT

A group of plant arrangement drawings were prepared by the architect-engineer as

a preliminary step to evaluating construction costs.

PLOT PLAN

The plant plot arrangement is based on receiving coal and limestone by rail and

shipping fly ash off-site by rail. A 60 day pile of coal and limestone is provided. Silos to

hold 15 days' accumulation of dry fly ash are provided adjacent to the rail terminal. A

series of small ponds catch run-off water from the site and provide for treatment of all

water returned to the North River.

Figure 9 shows the plot arrangement. The smaller overall plot layout indicates the

dominant aspect of one 3600 foot by 3600 foot (1097 by 1097 m) sludge pond. The upper

detail shows that at the active site half the area will be used for coal storage and for

cooling towers. The boiler house abuts the turbine building. The electrostatic

precipitators are of substantial size in order to achieve 98.6 percent particle removal. A

single stack serves the entire plant. The land area for the power generation plant is 92

acres (372,311 m2); the sludge ponds must aggregate an additional 1785 acres (7,223,640

m2) in close proximity to the main plant. A total area of 3 square miles will be required.

This requirement will severely constrain the siting opportunities for these plants.

The coal feed system provides transportation by belt conveyor from the line

storage pile to the transfer tower. Tramp iron is removed and large size frozen coal is

crushed to small size. Next, the coal is conveyed to the surge bin in the boiler house,

where vibrating feeders and two conveyor belts feed eight coal silos disposed on opposite

sides of the building. The filled silos guarantee eight hours of boiler output. Each silo

feeds a single coal pulierizer by a gravimetric feed. Coal drying and conveyance to the

burners is by hot .air. For startup and warmup an oil system firing no. 2 fuel oil is

provided, alo 4'0'0 ,000 gallons (379 m3) of fuel storage in two tanks.

GE &k?,tANGEMENT

A more detailed general arrangement plan for the turbine hall and boiler is

presented in Figure 10. The eight silos on either side of the boiler each hold an 8 hour coal

23

II SAOOO0SISCOOLINO TOWERS

COAL0 EAL TRCATLIE

C. ~ ~ ~ ~ ~LP1 IREC4ps.T WTRTI~ ~ TR~

TOTAL EM4E Ooo ~ I~~ .0! APLLO LT AREA

j14C0 LOTE PLL.AP "=O C1tNO

E~ lI CC7I4TMQ.L RE

A.,WlEA ... LIRE.

LIFiur PlotS~ CovntoaL . Stea PlantRR. Plan forEN

A

UA I,,gY --- - "I' aJ-----

PLAN AT EL 51'

CISC WAVER

'I'

" I ,--------4 F 7 7 ..... A)'W s 2 I~ h

--

lotk_ G PLAN L t I Sb

g- ,g:o - -rl UIu l ,v_,\II

Figure 10. Turbine and Boiler Buildings

25

supply, and all feed to one coal pulverizer. The air preheaters and fuels to the

electrostatic precipitators of Figure 8 dominat the leftside. The ground level of the

turbine hall on the right indicates the arrangement of the many support functions for the

steam turbine cycle.

The general arrangement elevation view shown in Figure 11 combines the boiler

details Of Figures 3 and 4 in a proper orientation to the turbine hall and the flue gas

exhaust system detailed in Figure 8. The arrangement provides short steam lines and

liberal access space for all apparatus. At the extreme left, the gas enters the flue gas

system of Figure 8 at the electrostatic precipitators.

The four electrostatic precipitators shown in Figure 8 are especially voluminous, to

provide the low gas velocities essential to the capture of 98.6 percent of the entrained fly

ash. Each unit is 54 feet (16.5 m) high, 93 feet (28.4 m) wide, and 44 feet (18.4 m) deep.

The entry and exits are divided in two to retain normal flue connections. Each unit is

serviced by one induced draft fan working in the cleaned gas leaving the unit. The six wet

gas scrubbers and reheaters then deliver the flue gas to a single 500 foot (152 m) stack.

ELECTRICAL SCHEMATIC

Figure 12 is a single-line diagram showing major electrical equipment. The single

steam turbine-generator at 24kV feeds two main transformers to 500 kV and two auxiliary

transformers to 13.8 kV. A startup transformer may also feed the 13.8 kV bus from the 500

kV transmission line. Major and subsidiary buses are identified, as well as major auxiliary

electrical loads.

26

FURlNACE AATR SQDtuV

P¢1AI ERECR -

SAIL MIL PtJLeIlICR

SECTION SCArS I -ZO

A-A

LEGEND

PA PRIMARY A pp H I .HPR , EZU

L P LOW PfOSSJPJ

Figure 11. Elevation View of General Arrangement

0 0tL~ LW1= 6.

T.

*A~~uFigur 12.hA Majo Elect~6k~rcal Equimen

Section 5

SYSTEM PERFORMANCE AND COST

PERFORMANCE INTEGRATION

Evaluation was made of plant performance on the average 59 F (288 K) day with all equipment operating at 100 percent condition with respect to its design and specification point. To adjust performance data so that an exact integration results, a detailed steam

turbine heat balance had been made at the 100 percent operating point, as presented in

Figure 5. The required 6867.4 MBtu/h (1.13 GJ/s) from the boiler were deemed to be

provided at the exact boiler efficiency (87.1346) that prevails with the 5 percent margin

condition detailed in the boiler heat balance (Figure 4). Typically, boiler efficiency improves slightly'at reduced firing rates.

In addition to the coal fired at the boiler, the rate of coal usage for calcining was evaluated on the basis that the mass flows of the wet gas scrubber process flow diagram

(Figure 7) represent operation at a 5 percent margin above the required 100 percent level.

Table 9 presents the basis and results for the integration into the steam cycle of boiler

and wet gas scrubber operating flow rates.

Table 9

ENERGY BALANCE-100 PERCENT RATING, 59 F DAY

CONVENTIONAL STEAM PLANT-WET SCRUBBERS--250 F STACK

Parameter Value

Generated Power 819938 kw

Heat-to-Steam Cycle1 6867.4 M]tu/Hr

HHV of Fuel Fired2 7881.4 MBtu/Hr

Coal Fired at Boiler3 730570 pph

4

Coal Fired at Calciner 13810 pph

Total Coal Rate 744380 pph

Effective Boiler Efficiency 85.52 percent

Limestone Feed Rate4 119050 pph

Scrubber Makeup Water Rate 917 gpm

Notes: 1 From 100 percent steam cycle heat

balance, Figure 5

2 Boiler efficiency 0.871346 from heat

balance, Figure 4

3 Based on 10788 Btu/pound higher heat

ing value (RHV)

4 Rates proportioned 1/1.05 for wet

scrubber, Figure 7

29

SYSTEM OUTPUT

For the 100 percent operating point Table 10 shows that the 820 MW of generator

output was reduced to 747 MW net plant output by the 73 MW requireq for auxiliaries.

The auxiliary loss breakdown is presented in Table 11. The induced fan power requirement

Table 10

SYSTEM OUTPUT

CONVENTIONAL STEAM PLANT-WET SCRUBBERS--250 F STACK

Parameter Evaluation

Steam Cycle Output 819.9 MW

Total Auxiliary Losses 72.7 MW

Net Power Plant Output 747.2 MW

(60 Hz AC-500kV)

Table 11

AUXILIARY LOSS BREAKDOWN

CONVENTIONAL STEAM PLANT-WET GAS SCRUBBERS-250 F STACK

NO.OF TOTAL ITEM ASSUMPTIONS UNITS MWe

FURNACE

FD FANS 19"& P,0.82 EFF 4 7.3 PA FANS 42"'A P,0.82 EFF 4 2,9 IDFANS 23" 4 P 0 78 EFF 4 8.8 ESP 695,000 CFM, 300 F,0 986 EFF 45 2 PULVERIZERS 8 7.6

31 8 TURBINE AUXILIARY 0.33% OF GROSS kW 1 2 8

WET SCRUBBER 100

MAJOR PUMPS

BOOSTER 600 PSI, 6MILLION #, 75% x 90% 2 37 CONDENSATE 185 PSI, 3 9 MILLION #, 70% x 90% 2 1.0 CIRC WATER PROPORTION TO COOLING 3 4 8

HEAT DUTY 95

WATER INTAKE A/E ESTIMATE 2 0 9

SOLIDS HANDLING BASED ON RATES AND LIFTS 1 3.0

"HOTEL" LOADS A/E ESTIMATE 1%OF 1 8.3 GENERATION

COOLING TOWER FANS PROPORTIONAL TO HEAT DUTY 20 2 3

TRANSFORMERS 0 5% OF GROSS GENERATION 4 4 1

TOTAL AUXILIARY POWER = 72.7

30

was 4 MW greater than normal as a result of the additional 9 inch drop in water pressure

in the wet gas scrubbers; the scrubber system itself consumes 10 MW. All other values are

typical of current steam plants. These auxiliary loads consume 8.9 percent of the

generator output in the plant.

COSTS-GENERAL

Costs were synthesized from the costs of major components, balance of plant materials, and balance of plant labor. An equipment list of major items in-the balance of

plant was made to assure completeness and to assure that the selected equipment ratings

would match the extreme requirements for continuous operation. A detail6d breakdown of

balance of plant direct labor in man-hours and of material costs completes the

identification of all items of construction and installation costs. To these are added

indirect field labor costs and major component costs. An architect-engineering fee is

added in proportion to the engineering effort. To the sum total a contingency is applied,

to be expended on items not directly counted in a preliminary appraisal such as this.

Finally, a factor of 0.548 is added to the total for escalation and interest during

construction for the 5.5 year period.

MAJOR COMPONENT CHARACTERISTICS

The steam generator characteristics are listed in Table 12. The heat-delivered

efficiency of 87.1 percent would improve approximately 1.2 .percent if the flue gas were

reduced in temperature to 250 F (394 K) rather than the 300 F (422 K) level dictated by

the high level of sulfur in the fuel. The radiant surfaces in the -furnace experience a heat

flux four times the average, while the more extensive convection surfaces experience

twothirds the average heat flux.

Table 12

HEAT EXCHANGER CHARACTERISTICS

CONVENTIONAL STEAM-WET GAS SCRUBBERS-250 F STACK

OUTPUT OR UNIT UNIT VESSEL DUTY PER WEIGHT COST SURFACE HEAT FLUX

NO. OF SIZE OR UNIT (FOB) {FOB) AREA AVERAGE HEATEXCHANGER UNITS TYPE MUIU EFFICIENCY MLB M$ FT. BtuI(HR FT'

STEAM GENERATOR 1 130x90'x282' 6867 87.1% 40.35 39.73 - 610,000 11,670

72,000* 44,745*

538,000 t 7,247 t

RADIANT FURNACE SURFACES

t CONVECTION SURFACES

31

The cost of $39.73 million (mid-1975) includes the air preheater, flues and ducts,

coal pulverizers, and supporting steel and platforms. Excluded are the cost of the fans

which appear as balance of plant, and the 6.15 million dollar cost of the electrostatic

precipitators with their support steel.

Table 13 shows the cost of the steam turbine-generator at $26 million and expresses

the cost per pound and per unit of energy concerned.

Table 13

MAJOR COMPONENT AND SUBSYSTEM WEIGHTS AND COSTS SUMMARY CONVENTIONAL STEAM-WET GAS SCRUBBERS--250 F STACK

COMPONENT OR SUBSYSTEM COST PER

WEIGHT COSTS OUTPUT UNIT COST MAJOR COMPONENT

OR SUBSYSTEM (FOB)M LBS

4FOB)MS

OR DUTY

OUTPUT OR DUTY

PER LB

PRIME CYCLE

STEAM TURBINE-GENERATOR 65 26.0 819.9MW8 31.7 $/kWe 4.0$/LB

(GENERATOR ALONE) (0940) - 819.9MWe --

STEAM GENERATOR 40.35 39.73 2013 MWth 19.74 $/kWth 0.98$/LB

MAJOR COMPONENT AND SUBSYSTEM CAPITAL COST

A more detailed discussion of ultimate costs can be made by including the balance

of plant materials and direct and indirect labor costs. Table 14 shows such a compilation.

Table 14

MAJOR COMPONENT AND SUBSYSTEM CAPITAL COST SUMMARY CONVENTIONAL STEAM PLANT-WET SCRUBBERS-250 F STACK

COMPONENT OR SITE SUBSYSTEM LABOR TOTAL

NO OF COST/UNIT

(FOB) COSTS (FOB)

BOP MATERIALS

(DIRECT + INDIRECT)

INSTALLED COST

MAJOR COMPONENT OR SUBSYSTEM UNITS MS MS MS MS M$

FUEL HANDLING & PREPARATION

COAL AND SOLIDS HANDLING - - - 922 272 1194

PRIME CYCLE

STEAM TURBINE-GENERATOR I 26 0 260 0.10 268 2878

CONVENTIONAL STEAM GENERATOR 1 3973 3973 848 231 71 31

ELECTROSTATIC PRECIPITATORS 4 1 54 6 15 0 22 234 871

COOLING TOWERS 20 - - 361 317 678

PUMPS, HEAT EXCHANGERS, STACKS - - - 1 32 3 48 14 80

PIPING, ETC - - 1400 2233 3633

GAS CLEANUP SYSTEM

WET LIME SCRUBBERS 3036 21 54 51 90

32

The conventional steam generator with the coal and solids handling aggregate $85 million;

the gas cleanup comprising electrostatic precipitators and wet lind scrubber subsystem

total $60 million. The steam turbine generator is of the order of $30 million.

It is evident that comparisons based on component costs alone would give

proportions totally different from that for the item, including installation costs. Balance

of plant equipment and costs therefore merit a detailed evaluation.

BALANCE OF PLANT EQUIPMENT LIST

Specifications for balance of plant equipment are presented in Table 15 as prepared by the architect-engineer (Bechtel). The specifications are based on continuous operation

at the valves wide open (VWO) condition for the steam turbine flow rates. The boiler and

wet scrubbers have comparable margins.

The electric motor drives for pumps and fans are sized for additional margins of 10

percent on flow, 20 percent on static pressure rise, and approximately 30 percent on

power. All of these specifications are for equipment more than sufficient to match the

100 percent operating condition.

BALANCE OF PLANT CAPITAL COSTS

Table 16 presents the architect-engineer's detailed breakdown of the direct manual

field labor in thousands of man-hours (MH 1000's), and of balance of plant material cost in

thousands of dollars ($1000's) for each major category of the balance of plant. An average

hourly field labor rate of $11.75 in mid-1975 dollars is used to convert man-hours to dollars.

Where indirect field labor is allocated to individual items rather than the total labor for

the job, it is apportioned as 90 percent of the direct field labor, which is equivalent to

$10.58 per hour.

The seven major categories used by the architect-engineer relate to the principal

field labor skills to be applied. An approximate distribution of costs was also made, using

the following categories:

1. Land improvements and structures

2. Coal handling

3. Prime cycle plant equipment

4. Bottoming cycle (not applicable to this plant)

5. Electrical plant and instrumentation

The appropriate subdivision number for each item or major category in Table 16 is

indicated in parentheses after its title.

33

Table 15

BALANCE OF PLANT EQUIPMENT LIST CONVENTIONAL STEAM PLANT WITH WET LIME SCRUBBERS

250 F EXHAUST GAS TEMPERATURE

Eqpt. No. Service Description

1.0 Coal & Limestone Handling Systems

C-1 Coal Conveyor Belt 60 in wide, 340 ft long, 3000 tph

C-2 U "t 760 ft " 1.

C -3 " " " U " 1 9 0 f t " 1.

c-4 a U 42 in " 980 ft 500 tph

c-5 i 1 , I t 540 ft " 'a

C-6 ma " " 170 ft a " "

C-7 " " " 110 ft " at

C-8St " (2 req'd.) 30 in " 160 ft 300 tph

C-9 Limestone Conveyor Belt 60 in " 500 ft " 3000 tph

C-10 " " " 24 in " 630 ft 65 tph

C f "1 it " a 42 0 ft " a a

C-12 Limestone Bucket Conveyor U " " 120 ft " 100 tph

0-13 Traveling Grate-Kiln 650 ton/day nominal lime production System (Package) (880 ton/day design capacity), 12 ft

wide x 48 ft long traveling grate, 13 ft I.D. x 180 ft long rotary kiln with Niems

type cooler. Includes coal grinding/ firing equipment, control panel/instrumentation, all refractories and drives, induced draft fan, baghouse dust collector and ducting.

C-14 Coal Conveyor Belt 18 in wide, 60 ft long, 20 tph

C-15 Lime Bucket Conveyor 24 in wide, 140 ft long, 40 tph (2 req'd.)

C-16 Fly Ash Silos (2 req'd.) Total Volume 833,184 ft , 80 ft dia x 85 ft high

2.0 Electrical Systems

E-1 Main Transformers (2 req'd ) 468 NA, FOA, 65 C, 24/500 kV

E-2 Unit Auxiliary Transformers 40/54/67 HVA, 65 C, OA/FA/FOA, (2 req'd.) 24/13.8 kV, 30, 60Hz

(sheet iof 3)

34

Table 15

BALANCE OF PLANT EQUIPMENT LIST

CONVENTIONAL STEAM PLANT WITH WET LIME SCRUBBERS

250 F EXHAUST GAS TEMPERATURE

Eqpt

No. Service Description

E-3 Emergency Diesal Generator 1000 kW, 30, 60 Hz, 480 V, 0.3 PF

E-4 Start-up Transformer 28/37.5/47 MVA, OA/FA/FOA, 500/13.8 kV,

FOA, 65 C, 30, 60 Hz

E-5 Miscellaneous 480V LCC Transformers (14 req'd.)

1689 kVA, OA, 65 C, 13.8 kV/489V/277V,

30, 60 Hz

E-6 Boiler Auxiliary Transformers (2 req'd.)

5500 kVA, OA, 65 C, 13.8/4.16kV, 30, 60 Hz

E-7 LCC Transformers (2 req'd.) 7000 kVA; OA, 65 C, 13.8/4.16 kV, 30, 60 Hz

E-8 Scrubber Transformers (2 req'd.)

5,000 kVA, OA, 65 C, 13.8/4.16 kV,

30, 60 Hz

3.0 Hain Fluid Systems

F-I

F-2

Main Condenser

Piping:

3.31 x 10 material.

ft of Heat Transfer Area Std.

Circulating Water I. D. = 114 in

Main Steam I. D. = 15.3 in, tm = 3.97 in

Boiler Feed Water I. D. = 26.53 in, tm = 0.675 in

Cold Reheat I. D. = 32.54 in, tm = 1.57 in

Hot Reheat I.D.- 18.1 in, tm = 2.25 in

F-3 Feedwater Heaters: Shell Press/Temp. psia/ F

Tube I Press/Temp. psia/ F

Flow (100%) lb/hr

Heat Transfer Area ft

LP #1 LP #2 LP #3 LP #4 IP H.P. DFT

5/163 11/195 20/228 67/300 296/416 745/510 6.22x1O

210/158 210/190 210/223 210/295 1040/416

5,700/519 lb/hr, @ 353 F

4;05 x 10 4 05 x 10 4.05 x 10 4.05 x 10 6.22 x 10 6.22 x 10

14,330

13,550

13,720

18,770

45,660

49,700

F-4 Main Condensate Pumps and Motors (2 req'd.)

Vertical Centerline, 4250 gpm, 600 hp

motor, 410 ft TDA

F-5 Feedwater Booster Pumps & Motors (2 req'd.)

7,300 gpm, 3850 hp, 1510 ft TDH

(sheet 2 of 3)

35

http:13.8/4.16http:13.8/4.16

Table 15

BALANCE OF PLANT EQUIPMENT LIST

CONVENTIONAL STEAM PLANT WITH WET LIME SCRUBBERS

250 F EXHAUST GAS TEMPERATURE

Eqpt.

No.

F-6

F-7

F-S

F-9

F-10

F-i

F-12

F-13

F-14

F-15

F-16

Service

Main Boiler Feed Pumps &

Turbine Drivers (3 req'd.)

Main Circulating Pumps and

Motors (3 req'd.)

Cooling Towers (20 Cells)

Forced Draft Fans (2 req'd.)

Primary Air Fans (2 req'd.)

Electrostatic Precipitators

(4 req'd.)

Scrubber - Turbulent

Contact Absorber (6 req'd.)

Air Heater (6 req'd.)

Induced Draft Fans (4 req'd.)

Forced Draft Fans for

Reheater Air (6 req'd.)

Exhaust Stack

Description

4900 gpm, 12,600 hp, 8,300 ft TDH .

82,000 gpm, 2250 hp, 75 ft TDR

246,000 gpm

Operating

Test Block

Motor

971,000 cfm @ 80 F, S 19 in wg 0 1,165,000 cfm @ 105 F 24.7 in wg 6500 hp

.P. =

, S.P.

Operating

Test Block

161,750 cffm @ 96 F, S. 19 in wg, S.F. outlet 194,000 cfm @ 121 F, 19 in wg, S.P. outlet in wg

P. inlet =

=

42 in wg S.P. inlet

54.6

Motor 2250 hp

Each 54 ft high x 92 ft wide x 44 ft long,

1,262,000 lb, 1296 kVA, 99%-particulate

removal efficiency, 695,000 acfm @ 3000 F.

Each 60 ft high x 40 ft wide x 18 ft long,

316L-S.S., neoprene lined, 3 stages,

450,000 acfm @ 312?F & 13.9 psia.

Each 4.5 ft high x 21.5 ft wide x 37.5 ft

long .

Operating 660,000 cfm @ 300 F, Total S.P. = 23 i wg

Test Block 800,000 cfm Q 3250F, Total S.2. = 30 in wg

Motor 5,000 hp

Operating 545,000 cfm @ 80 F, Total S.P.

3.5 in wg 0

Test Block 654,000 cfm @105 F, Total S.P. = 4.55 in wg

Motor 650 hp

40 ft I.D., 500 ft high

(sheet 3 of 3)

36

Table 16

BALANCE OF PLANT ESTIMATE DETAIL FOR CONVENTIONAL STEAM CYCLE-

WET GAS SCRUBBER-250 F STACK

Direct Manual Field Labor MH 1000's

Balance of Plant Material

$ 1000's

1. 0 STEAM GENERATOR (3)

1. 1 Steam Generator Erection

- Erect only fsupply by others): includes heat transfer surface and pressure 544 parts; buckstays, braces and hangers; fuel-burning equipment; accessories; soot and ash equipment; control systems; brickwork, refractory and insulation

- Supply and erect: includes support steel and access steel for above; 296 6,800 miscellaneous materials and labor operations

1. 2 Steam Generator Auxiliaries

- Erect only (supply by others): 185 includes P.A. fans, air preheater; flues and ducts to precipitators; insulation for flues and ducts; pulverizers, feeders and hoppers

- Supply ani erect: 12 1.680 includes F.D. Fans (2 @ $390,000 ea*); I.D. fans (4 @$ZZ0, 000 ea.-)

1. 3 Electrostatic Precipitators

- Erect only (supply by others): 99 includes electrostatic precipitators

- Supply and erect: 4 220 indludes support steel for precipitators

1,140 8,700

2.0 TURBINE GENERATOR (3)

Install only (supply by others): 120 100 includes 835 MWe steam turbine; generator; exciter, auxiliary equipment, integral steam and auxiliary piping; insulation; miscellaneous labor operations

*based on suppliers' verbal budgetary quotations

(sheet I of 7)

37

Table 16

BALANCE OF PLANT ESTIMATE 'DETAIL FOR CONVENTIONAL STEAM CYCLE-

WET GAS SCRUBBER-250 F STACK

Direct Manual Balance of Field Labor Plant Material MH 1000's $ 1000's

3.0 PROCESS MECHANICAL EQUIPMENT

3.1 Boiler Feedwater Pnmps (3)

includes turbine-driven main feedwater pumps 10 3, 2Z0 and drivers (3@ $940, 000 ea. *); feedwater booster pumps and motors (2 @ $125, 000 ea.

3.2 Main Circ. Water Pumps (3)

includes main circ. water pumps and motors 3 700 (3 @$220, 000 ea*)

3. 3 Other Pumps (3)

includes condensate pumps and motors (2@ 5 650 $85,000 ea.'-); and other pumps and drivers not listed elsewhere

3.4 Main Condenser* (3)

includes shells; tubes; air ejectors 16 2,120

3.5 Heaters, Exchangers, Tanks and Vessels (3)

includes l.p. feedwater heaters (4): i.p. feed 9 3,060 water heater; h.p. feedwater heater; deaerating heater and storage tank; miscellaneous heaters and exchangers; tanks and vessels

3.6 Stack and Accessories (3)

includes concrete stack and liner-; lights and 113 1, 570 marker painting; hoists and platforms, stack foundation

3.7 Turbine Hall Crane (1)

includes crane and accessories 3 410

3.8 Coal Handling (2)

includes railcar dumping equipment; dust 61 5,640 collectors; primary and secondary crushing equipment; belt scale; sampling station; magnetic cleaners; mobile equipment; conveyors to pile; reclaiming feeders; conveyors to coal silos; coal silos

*based on suppliers' verbal budgetary quotations (sheet 2 of 7)

38

Table 16

BALANCE OF PLANT ESTIMATE DETAIL FOR CONVENTIONAL STEAM CYCLE-

WET GAS SCRUBBER-250 F STACK

,Direct Manual Balance of

Field Labor Plant Material MI-H 1000's $ 1000's

3.9 Limestone Handling C3)

includes magnetic cleaners; conveyor to lime 22 1,250 stone pile; reclaiming feeders; belt scale; conveyor s to calciner

3.10 Ash Handling (2)

includes bottom ash system, fly ash handling 61 3, 580 system for precipitators and air preheater;

ash conveyors; ash storage silos (2) with feeders,

unloaders and foundations; railcar loading

equipment

3. 11 Cooling Towers- (3)

includes mechanical draft towers with fans and 52 2,230 motors

3.12 Other Mechanical Equipment (3)

includes water treatment and chermcal injection; 30 1,660 air compressors and auxiliaries; fuel oil ignition and warm-up; screenwell, rmscellaneous plant equipment, equipment insulation

3.13 Scrubber Ductwork (3) 207 3,270

- includes flue gas duct outboard of electrostatic precipitators; duct lining; duct insulation; dampers and expansion joints

3.14 Scrubber Flue Gas Equipment (3) 27 3,090

- includes F.D. fans for flue gas reheat (6 @ $200, 000 ea. '*), air heaters for flue gas reheat (6 @ $280, 000 ea-)

3.15 Wet Lime S02 Scrubbers (3) 86 6,930

- -ncludes complete SO2 scrubber vessels with presaturator and mist eliminator systems (6 @$1, 000, 000 ea*-)

*based on suppliers' verbal budgetary quotations

(sheet 3 of 7)

39

Table 16

BALANCE OF PLANT ESTIMATE DETAIL FOR CONVENTIONAL STEAM CYCLE-WET GAS SCRUBBER-250 F STACK

Direct Manual Balance of Field Labor Plant,Material MH 1000's $ 1000's

3.T6 Scribber tLf e-System (-3- 66- ---3;660

- includes limestone calciner with travelling

grate kiln ($2, 700, 000*); Kiln stack;*coal

conveyor, bucket elevator and storage bin

for kiln; lime conveyor, bucket elevator and

storage silos; lime slaker ($IZ0, 000*)

3.17 Scrubber System Pumps (3) 10 1,080

- includes slurry recycle (18 @ $40, 000 ea*);

mist eliminator wash (3 @ $25, 000 ea.*f;

slurry storage and transfer (4 @ $4,000 ea*);

slurry feed (3 @ $5, 000 ea*), pond feed tank

(3 @ $10, 000 ea*); pond feed booster (2 @

$15,000 ea*); pond water recycle and

booster (4 @$12, 500 ea*),

3. 18 Scrubber System Tanks (3) 4 2,180

- includes tanks and agitators for absorber effluent

hold, pond feed, entrainment separator surge,

slurry surge, slurry storage, slurry transfer

785 46,300

4.0 ELECTRICAL (5)

4. 1 Main Transformers * 4 2,020

4.2 Other Transformers* and Main Bus 17 1, 280

- includes startup transformer; station service

transformers including those for scrubber

system, generator main bus

4.3 Switchgear and Control Centers 42 3,400

- includes switchgear and load centers; motor

control centers, local control stations, dis

tribution panels, relay and meter boards

4.4 Other Electrical Equipment 363 2,010

- includes communications, grounding, cathodic

and freeze protection; lighting, pre-operational

testing

*based on suppliers' verbal budgetary quotations

(sheet 4 of 7)

40

Table 16

BALANCE OF PLANT ESTIMATE DETAIL FOR CONVENTIONAL STEAM CYCLE-

WET GAS SCRUBBER-250 F STACK

Direct Manual Balance of Field Labor Plant Material

MH 1000's $ 100O!s

4.5 Auxiliary Diesel Generator 2 110

- includes diesel generator, batteries and

associated d.c. equipment

4.6 Conduit, Cable Trays, Wire and Cable 632 4,080

1,060 12,900 5.0 CIVIL AND STRUCTURAL

5.1 Concrete Substructures and Foundations (1) 340 2,800

- includes turbine and boiler building sub

structure; coal, limestone and ash handling

foundations, pits and tunnels; miscellaneous

equipment foundations; auxiliary buildings

substructures; miscellaneous concrete

5.2 Superstructures (1) 275 7,960

-. includes turbine building, auxiliary yard

buildings; boiler enclosure

5.3 Earthwork (1) 130 300

- includes building excavations; coal, limestone

and ash handling excavations; circ. water

system excavations, miscellaneous foundation

excavations; dewatering and piling

5.4 Cooling Tower Basin and Circ. Water System (3) 90 1,380

- includes circ. water pump pads, riser and

concrete envelope for pipe; cooling tower basin;

circ. water pipe; cooling tower miscellaneous

steel and fire protection

5.5 S02 Scrubber Civil and Structural (1) 180 3,660

- includes foundations, earthwork and structures

particular to scrubber equipment

1,015 16,100

(sheet 5 of 7)

41

Table 16

BALANCE OF PLANT ESTIMATE DETAIL FOR CONVENTIONAL STEAM CYCLE-

WET GAS SCRUBBER-250 F STACK

Direct Manual Balance of Field Labor Plant Material MH 1000's $ 1000's

6.0 PROCESS PIPING AND INSTRUMENTATION

6.1 Steam and Feedwater Piping (3) 81 3,850

- includes main steam; extraction steam; hot

reheat; cold reheat; feedwater and condensate

large piping, valves and fittings

6. Z SOZ Scrubber System Large Piping (3) 53 2, 630

- includes make-up water; resaturation slurry

water; mist eliminator wash; absorber slurry

effluent tank overflow; pond feed; pond recycle

water; lime slurry piping; recycle slurry

piping; air heater steam supply; air heater

condensate return

6.3 Other Large Piping (3) 231 4,050

- includes auxiliary steam; process water;

auxiliary systems

6.4 Small Piping (3) 152 1,350

- includes all piping, valves and fittings of 2 inch

diameter and less

6.5 Hangers and Misc. Labor Operations (3) 420 1,460

- includes all hangers and supports; material

handling; scaffolding; misc. labor operations

6.6 Pipe Insulation (3) 63 660

6.7 Instrumentation and Controls (5) 220 4,900

1,220 18,900

7.0 YARDWORK AND MISCELLANEOUS (1)

7.1 Site Preparation and Improvements 87 10

- includes soil testing; clearing and grubbing;

rough grading; finish grading; landscaping

7.2 Site Utilities 5 50

- includes storm and sanitary sewers; nonprocess service water

(sheet 4 of 7)

42

Table 16

BALANCE OF PLANT ESTIMATE DETAIL FOR CONVENTIONAL STEAM CYCLE--

WET GAS SCRUBBER-250 F STACK

Direct Manual Balance of Field Labor Plant Material. MH 1000's $ 1000's

7.3 Roads and Raliroads 27 740

- includes railroad spur; roads, walks and parking areas

7.4 Yard Fire Protection, Fences and Gates 52 600

7.5 Water Treatment Ponds 88 20

- includes earthwork; pond lining; offsite pipeline

7.6 Lab, Machine Shop and Office Equipment 1 280

260 1,700

(sheet 7 of 7)

43

PLANT COST ESTIMATE

The major components from Table 14 and the balance of plant costs appropriate to

each of the categories of field labor skills used in Table 15 are combined in Table 17 show a

total of $301.62 million.

Table 17

PLANT CAPITAL COST BREAKDOWN

CONVENTIONAL STEAM PLANT-WET GAS SCRUBBERS-250 F STACK

COSTS (MILLIONS OF DOLLARS) CATEGORIES COMPONENTS DIRIECI LABOR (1) INDIRECT FIELD 2) MATERIALS(3) TOTAL

1.0 STEAM GENERATORS 45.88 1340 12.06 8.70 8004

20 TURBINE GENERATOR 26.00 1 41 1 27 0.10 28.78 3 0 PROCESS MECHANICAL EQUIPMENT 9 22 8 30 46 30 63 82

4 0 ELECTRICAL 12.46 1121 1290 3657

5 0 CIVILAND STRUCTURAL 11 93 10.73 1610 3876

6 0 PROCESS PIPING AND INSTRUMENTATION 14.34 12.90 18.90 46.14

7 0 YARDWORK-AND MISCELLANEOUS 3.06 2.75 1.70 7 51

71 88 65.82 59.22 104-70 301 62

BOP LABOR, MATERIALS & INDIRECTS 229.74 (SUM OF 1 + 2 + 3)

A/E HOME OFFICE &FEE @ 15% 34 50

TOTAL PLANT COST 336 12

CONTINGENCY 0) 20% 67 22

TOTAL CAPITAL COST 403 34

The home office and fee of 15 percent is applied only to the balance of plant costs.

A contingency of 20 percent of all prior costs is applied to cover expected costs not

specifically included in the original estimating process. The total capital cost of $403

million represents $492/kW based on total generation, or $540/kW based on net station

output.

A reallocation of costs according to equipment function is presented in Table 18.

Items 1 through 6 include everything in the preceding table. Item 7 adds the value of

escalation and interest during the 5.5 year construction time. This item is 55 percent of

the prior total. The result is a final plant cost of $761/kW of total generation, or $835/kW

of net station output.

44

Table 18

PLANT CAPITAL COST ESTIMATE SUMMARY

CONVENTIONAL STEAM PLANT-WET SCRUBBERS-250 F STACK

(Approximate Distribution)

MAJOR BOP SITE LABOR COMPONENTS MATERIALS (DIRECT & INDIRECT TOTAL

MS MS M$ M$

16.8 265 43.4

(LAND, PLANT AREA 92 ACRES)

(LAND, 30-YEAR DISPOSAL 1785 ACRES)#

0 92 2.7 11.9

1 0 LAND IMPROVEMENTS &STRUCTURES

20 COAL HANDLING

71 9 609 67.2 199.930 PRIME CYCLE PLANT EQUIPMENT

4 0 BOTTOM CYCLE NOT APPLICABLE

5 0 ELECTRICAL PLANT & INSTRUMENTATION 0 178 286 464

301 6SUBTOTAL 71.9 104 7 1250

60 A-E SERVICE 8 CONTINGENCY 101 7

7 0 ESCALATION & INTEREST DURING 221 0

CONSTRUCTION TOTAL Ms 624.3

PLANT OUTPUT MW 747.2

TOTAL $/kW 835.4

*COST INCLUDES LAND PREPARATION FOR 5YEAR DISPOSAL.

45

Section 6

NATURAL RESOURCES AND ENVIRONMENTAL INTRUSIONS

The natural resources required for this plant are listed in Table 19. The sorbent use

is low because of the highly efficient chemical system. The high coal use reflects a

reduced generation due to steam diversion for reheating and, in addition, added auxiliary

power consumed in the wet gas scrubber system and in the induced draft fans. The water

usage is mostly for the cooling tower and is at conventional levels.

Table 19

NATURAL kESOURCE REQUIREMENTS

CONVENTIONAL STEAM PLANT-WET GAS SCRUBBERS-250 F STACK

Parameter Value

Sorbent, Limestone lb/kWh 0.16

Coal, lb/kWh 0.996

Water, Total (gal/kWh)

Cooling

Evaporation 0.56

Blowdown 0.18

Plant General Use 0.01

Sulfur Cleanup Use 0.07

Total Land, acres/100 MWe

Main Plant 12.3

Disposal Land 239.0

The large land area consigned to sludge accumulation suggests that some innovative

exploitation of the sludge might reduce this element of resource wastage. To a certain

degree the sludge ponds may represent an ongoing threat to the surroundings. Their

reclamation for agriculture or their use as a chemical resource could offset the liability of

their accumulatVin.

The 1 nmental intrusions are enumerated in Table 20. The sulfur emissions are

three-r t ;,' of the allowed 1.2 lb/MBtu (2.5 Kg/GJ). This results from 90 percent cap.Jo ,nereas 83 percent capture would just equal the limit. The NOKsN x released would

4at 4 just under the current limit by the use of staged combustion in firing the boiler. stack gas reheaters place a greater fraction of heat rejection at the stack as

compared with other plants.

47

Table 20

ENVIRONMENTAL INTRUSION CONVENTIONAL STEAM PLANT-WET GAS SCRUBBERS-250 F STACK

LB/MBtu LB/kWhEMISSIONS INPUT OUTPUT

SOx 0.867 0.0093 NOx 0.65 0.0070 HC

PARTICULATES 0.092 0.00099

THERMAL POLLUTION HEAT, REJECTED COOLING TOWERS, Btu/kWh 4188 HEAT, REJECTED STACK, Btu/kWh 3130* HEAT, REJECTED TOTAL, Btu/kWh 7318

WASTES LB/kWh M LB/DAY

WATER DISCHARGE 1.59 28 4 DRY FLY ASH 0.07 1.30 SLUDGE 0 19 3.46

*INCLUDES ALL SYSTEM LOSSES EXCEPT THE HEAT REJECTED BY THE COOLING TOWER SYSTEM.

SENSITIVITY TO EMISSION TARGETS

The chemical processes in use for wet scrubbing and for combustion do not lend

themselves to drastic changes in current emission targets. If the sulfur emission target

were to be half the current level, the scrubbers would increase in size and gaseous

pressure drop by a factor of 50 percent. The auxiliary power loss in the scrubber system

would tend to increase by approximately 5 MW. Reduction in particulate emissions would

require an increase of electrostatic precipitators of 100 percent to reach 0.05 lb/MBtu (0.1

kg/GJ), or half the current standard.

The reduction of NO x would be particularly difficult, since there is already a

burden of fuel-bound nitrogen to which the thermal NO x is added. Reduction to half the current standard is not currently deemed feasible.

48

. Section 7

SUMMARY OF PERFORMANCE AND COST

Table 21 summarizes the performance and cost for a 747 MW steam plant using wet

gas scrubbers with 250 F stack temperature. The low overall plant efficiency of 32

percent is due to steam diversion for stack gas reheating and parasitic auxiliary loads

imposed by the wet gas scrubbing system. The coal rate of 1 lb/kWh was a typical plant

value 45 years ago.

Table 21

SUMMARY PERFORMANCE AND COST CONVENTIONAL STEAM PLANT-WET GAS SCRUBBERS--250 F STACK

ITEM

NET POWER PLANT OUTPUT (MWe - 60Hz -500 kV) 747.2

THERMODYNAMIC EFFICIENCY (%) 40.7

POWER PLANT EFFICIENCY (%) 31.8

OVERALL ENERGY EFFICIENCY (%) 31.8

COAL CONSUMPTION (LB/kWh) 0.996

TOTAL WASTES (LB/kWh) 0,27

PLANT CAPITAL COST ($MILLION) 624.3

PLANT CAPITAL COST ($/kWe) 835.4

COST OF ELECTRICITY. CAPACITY FACTOR = 0 65

CAPITAL (MILLS/kWh) 26.4

FUEL (MILLS/kWh) 10.7

MAINTENANCE &OPERATION (MILLS/kWh) 2.6

TOTAL (MILLS/kWh) 39.8

ESTIMATED TIME OF CONSTRUCTION (YEARS) 5.5

The high plant costs result from the additional costs of the scrubber system and the

reduction of net output already noted. The net result is a cost of electricity (COE) of 39.8

mills/kWh, or 4 cents/kWh at the power plant boundary. The sensitivity of the cost of

electricity to these factors is presented in Table 22.

49

Table 22

COST OF ELECTRICITY (COE) SENSITIVITY

CONVENTIONAL STEAM PLANT WITH WET GAS SCRUBBERS

(250 F Stack Temperature)

Base Fuel Labor Capacity Factor

Cost Increase

Cost Increase

Materials Increase

Capacity Factor

0.65 50% 50% 50% Change

0.5 0.8 COE, Capital 26.4 26.4 32.2 33.9 34.3 21.5 COE, Fuel 10.7 16.1 10.7 10.7 10.7 10.7 COE, o&M 2.6 2.6 2.6 2.6 2.7 2.6 Total COE 39.8 45.2 45.5 47.2 47.8 34.8

50

Section 8

ALTERNATIVE PLANT CONSIDERATIONS

STACK GAS REHEAT TO 175 F

An appraisal was made for the identical boiler and scrubber configuration wherein

the stack gas was reheated to 175 F (353 K) instead of 250 F (394 K). Table 23 indicates

those elements that were unchanged, those elements that were significantly changed, and

some details of the greatly reduced stack gas reheat effect. The requirement for stack

gas reheat would be reduced by a.factor of 2.5. The reheat energy release from air heated

to 335 F (441 K) would increase by a factor of 1.9. The combined effect reduces the heat

duty on the steam reheaters to 23 percent of that required heretofore.

Table 23

CONVENTIONAL STEAM PLANT WET GAS SCRUBBERS-175 F STACK

FOR 175 F STACK IN PLACE OF 250 F STACK

NOT CHANGED

COAL RATE, AIR RATE, GAS RATE

SCRUBBER CONFIGURATION HEAT TO STEAM CYCI E

CHANGED

HEAT TO REHEAT STACK GAS REHEAT AIR FLOW STEAM TO STACK GAS REHEATERS

STEAM TURBINE CYCLE GENERATED POWER HEAT TO COOLING TOWERS

REHEAT EFFECTS 250 F 175 F RATIO

STACK GAS REHEAT FROM 125 F 125 F 50 F 2.5

AIR HEAT RELEASE FROM 335 F 85F 160F 1/1.9 AIR AND STEAM FLOW RATIOS 1 023 4.3

A revised*steam-turbine cycle heat balance was made to reflect these changes.

The major changes over values found on Figure 5 are tabulated in Table 24. The overall

energy balance of Table 9 would be unchanged except for the generated power. The

changes in Table 24 and the fixed values from Table 2 were used to reassess the auxiliary

power losses as presented in Table 25.

The system output as shown in Table 26 becomes 795.5 MW, an increase of 6

percent over the previous case with 250 F (394 K) stack.

51

I Table 24

STEAM TURBINE CYCLE CHANGES

FOR 175 F STACK VERSUS 250 F STACK

Parameter 250 F Stack 175 F Stack

Turbine Type TC4F33.5 TC4F33.5

Heat to steam, cycle, MBtu/Hr 6867.4 6867.4

Generator output, kW 819938 868620

Gross heat rate, Btu/kWh 8375.54 7906.13

Steam-to-gas reheater, lb/Hr 926,000 213,426

Last stage flow, lb/Hr 2,888,123 3,472,980

Condensate pump flow, lb/Hr 3,925,037 4,668,000

Heat to condenser, MBtu/Hr 3086 3638

Turbine cost, M$ 26.0 26.75

Table 25

AUXILIARY LOSS BREAKDOWN CONVENTIONAL STEAM PLANT-WET GAS SCRUBBERS-175 F STACK

NO.OF TOTAL ITEM ASSUMPTIONS UNITS MWe

FURNACE

FD FANS 19" a P,O 82 EFF 4 7.3

PAFANS 42" L P, 0-82EFF 4 2 9

ID FANS 23" A P, 0.78 EFF 4 88

ESP 695000 CFM,300F, 0 986 EFF 4 52

PULVERIZERS 8 76

31 8

TURBINE AUXILIARY 0 33% OF GROSS kW 1 2.9

WETSCRUBBER 86

MAJOR PUMPS

BOOSTER 600 PSI, 6 MILLION #, 75% x 90% 2 37

CONDENSATE 185 PSI, 4 7 MILLION #,70% x90% 2 1.2

CIRC WATER PROPORTION TO COOLING 3 5 6 HEAT DUTY 105

WATER INTAKE A/E ESTIMATE 2 0 9

SOLIDS HANDLING BASED ON RATES AND LIFTS 1 30

"HOTEL" LOADS A/E ESTIMATE 1% OF 1 84 GENERATION

COOLING TOWER FANS PROPORTIONAL TO HEAT DUTY 20 27

TRANSFORMERS 0 5% OFGROSSGENERATION 4 4.3

TOTAL AUXILIARY POWER = 73.1

52

Table 26

SYSTEM OUTPUT

CONVENTIONAL STEAM PLANT-WET SCRUBBERS-175 F STACK

Parameter Evaluation

Steam Cycle Output 868.6 MW

Total Auxiliary Losses 73.1 MW

Net Powerplant Output 795.5 MW (60 Hz AC-500 kV)

The revisions to the wet scrubber system relate entirely to the reduced steam and

air flows for the stack gas reheat. The lower table on Figure 7 shows these details for the

175 F (353 K) stack configuration. Tables 4, 6, and 8 show the changes in the scrubber

system cost details.

The overall plant arrangement details would not be changed. The increased

generation does change the size of electrical apparatus, a§ shown on Figure 13.

The balance of plant equipment list is presented in Table 27. The balance-of-plant

direct labor man-hours and material costs are presented in Table 28. These combine with

the major equipment costs to determine a plant cost of $396 million as detailed in Table

29. Table 30 redistributes the costs and adds on the escalation and interest during

construction. The results is a plant capital cost of $771 per kilowatt of net plant output. I

PERFORMANCE AND COST-175 F STACK

Table 31 summarizes the system performance and cost with 175 F (353 K) stack

reheat, and Table 32 compares the influence of 250 F (394 K) and 175 F (353 K) stack

reheat cases. On every measure the 175 F (353 K) stack shows advantage over the 250 F

(394 K) stack. The sensitivity of the cost of electricity to the several major variables is

presented in Table 33.

Natural resource usage and environmental intrusions would be comparable to values

in Tables 19 and 20, but there would be a 6 percent reduction where the basis was

kilowatt-hours.

NO SCRUBBER, 250 F(394 K)STACK ALTERNATIVE

It is instructive to apply the methodology of these evaluations to a plant in which

low-sulfur coal would be burned and the wet gas scrubbing system dispensed with. An

53

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4'Ell

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Fiur 1.2 ovntoa Stea Pln2ihWtGsSrbe-7

Table 27

EQUIPMENT LIST FOR CONVENTIONAL STEAM CYCLE-

EQPT.

NO. SERVICE

1. Coal,&

C-I Coal Conveyor Belt

C-2 " -"60

C-3 - ,

C-4 "

C-5 ,

C-6 , "

C-7 - " I

C-8 " " (2)

C-9 Limestone Conveyor Belt

C-10 It It

C-I " . "

C-12 Limestone Bucket Conveyor

C-13 Traveling Grate Kiln System (Package)

c-14 Coal Conveyor Belt

C-15 Lime Bucket Conveyor (2)

C-16 Fly Ash Silos (2)

WET SCRUBBERS, 175 F STACK

DESCRIPTION

Limestone Handling Systems

60 in wide, 340 ft long, 3000 tph

in 760 ft " 3000

60 in 190 ft 3000 "

42 in 980 ft " 500

42 in 540 ft 500

42 in 170 ft " 500

42 in 110 ft " 500

30 int 160 ft" 300"

60 in 500 ft " 3000 "

24 in 630 ft " 65

24 in 420 ft " 65

24 in 120 ft " 100

650 ton/day nominal lime production (880 ton/ day design capacity), 12 ft wide x 48 ft long

traveling grate, 13 ft I.D. x 180 ft long rotary

kiln with Niems type cooler. Includes coal

grinding/firing equipment, control panel/instru

mentation, all refractories and drives, induced

draft fan, baghouse dust collector and ducting.

18 in wide 60 ft long 20 tph

24 in " 140 ft " 40 1

Total Volume 833,184 ft 3 , 80 ft dia x 85 ft high

(sheet 1 of 4)

Table 27

EQUIPMENT LIST FOR CONVENTIONAL STEAM CYCLE-

WET SCRUBBERS, 175 F STACK

EQPT. No. SERV